Easily dispensed, anti-traction, mobility denial system

ABSTRACT

The present invention relates to a lubricious anti-traction material for effectively denying the mobility and access of personnel and vehicles to selected areas. The anti-traction material is composed of a slurry combined with water. The slurry is composed of an emulsion or dispersion and an anionic acrylamide polymer.

This is a Divisional application of U.S. patent application Ser. No.10/315,208, filed on Dec. 10, 2002 now U.S. Pat. No. 7,067,464, thecontents of which are incorporated herein in its entirety.

The U.S. Government has a paid-up license in this invention and theright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided by the terms of U.S. GovernmentContract No. V674-299F awarded by the United States Marine Corps.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a lubricious anti-traction material foruse in the control of crowds, riots, defense of positions (e.g.,military applications) and the like, and to a method of making the same.The anti-traction material may be quickly and easily applied to deterthe mobility and access of personnel and vehicles to restricted and/ordefended areas.

2. Description of Related Art

Crowd and riot control is a concern for law officials at every level ofgovernment: local, national and international. Attempts at controllingunruly gatherings and defending selected areas from such crowds haveresulted in physical and psychological injury to members of the lawcommunity and the crowds alike.

Typical attempts of crowd control often depend upon brute physical forceto subdue and disperse crowds. Such physical force includes batons,rubber bullets, water cannons, kinetic energy rounds and the like. Suchphysical force has resulted in injuries to both crowd members and lawenforcement officials, despite the use of riot gear or protectiveclothing, and often does not disperse unmanageable crowds.

Typically, disruptive riots occur on public streets or guarded prisons,wherein additional participants gather as the crowd moves towards itsmain objective. Dispersing such crowds and limiting forward movementwithout the use of physical force is highly desired.

Non-lethal weapon systems now represent an important alternative for lawenforcement officials and strategic defense purposes. Examples ofnon-lethal weapons include, but are not limited to, tear gas, flashgrenades, acoustic guns, sticky foams, snare nets, stun guns, strobelights, malodorants, etc.

In order to ensure the most desirable outcome in managing crowd control,it is desired that numerous alternatives to non-lethal weapons systemsbe available along a force continuum, such that a non-lethal weaponsuitable for a particular application may be selected based upon thenature of the threat and level of provocation.

In the case of slowing and/or eliminating the forward progress of rowdycrowds, several non-lethal controls have been utilized. These controlsrange from barriers, tear gas, malodorants, sticky foams, etc. However,these typical non-lethal controls have disadvantages. For instance,crowd barriers can be bulky, require advance planning to move them intoplace, require large storage areas when not in use, and can be destroyedor used as weapons by the crowd members, etc. Typical barriers may alsobe besieged by vehicles driven by crowd members. Crowd controls such astear gas and malodorants, although non-lethal, may still causephysiological and/or psychological injury to both law enforcement agentsand crowd members. Further, tear gas and malodorants may not impedeforward progress of determined rioters. Finally, sticky foams may bedifficult to remove once the crowd has dispersed.

Thus, a non-lethal impedance for crowd movement is desired that does notrequire much storage space and can be moved into place with minimalforethought. A crowd control means is desired that impedes not only themovement of crowds on foot, but also crowds in motorized vehicles. Sucha crowd control means should not induce significant physiological orpsychological injury, nor be able to be used by the crowds against thelaw enforcement officials. Further, the crowd control means should causelittle, if any, damage to the surrounding environment, and be easilyremoved once the crowd has been subdued and/or dispersed.

SUMMARY OF THE INVENTION

This invention identifies a composition for use as an anti-tractionmaterial that effectively deters the mobility and access of personneland/or vehicles to areas that are to be defended or protected. Itfurther immobilizes hostile crowds and enables authorities to constrainand apprehend unauthorized participants if desired.

The anti-traction material of the invention includes at least 1) aslurry of A) an anionic acrylamide polymer particle with B) an emulsionor dispersion of a polyacrylamide in a hydrocarbon that upon combinationwith 2) water, produces a very coherent, visco-elastic gel that resistsvertical slump and displacement by gravitational forces and forces offoot and vehicle traffic. The water is combined with the slurry uponimmediate application of the slurry to a targeted surface.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The components and preferred ratios in the composition are definedbelow:

Component 1: an emulsion or dispersion containing a polyacrylamide inwater and dispersed in an oil phase. This component may be a drillinghead lubricant or drilling mud additive, and preferably is an emulsionof a polyacrylamide in water emulsified in a hydrocarbon (e.g.,kerosene, petroleum distillates, vegetable oil, and mineral oil).Copolymers of polyacrylamides, polyacrylates, and polyacrylic acids workequally well, especially in an anionic form. Typical properties of thiscomponent include its “stickiness,” “viscoelasticity” (its ability toreturn to its original shape after being displaced), its rapid gel time,and the fact that the polymer chains relax and swell upon hydration.Examples of preferred Component 1 polymers include CYDRIL 5300 (ananionic polyacrylamide in water-in-oil emulsion), SUPERFLOC N-1986 (anonionic polyacrylamide in water-in-oil emulsion, and SUPERFLOC A-1885RS (an anionic polyacrylamide in water-in-oil-emulsion), all from CytecIndustries. In a preferred embodiment, this component comprises about75% of the two-part slurry, but can range from 60% to 80% and still beeffective.

Component 2: an acrylic polymer particle, preferably an anionicacrylamide polymer powder, which is combined with component 1 to producea slurry. The acrylic polymer particles are granular solids that rangefrom 0.5 mm to 2.0 mm in size. Upon hydration, the viscosity of thiscomponent increases to form a gel-like substance. Examples of preferredComponent 2 polymers include SUPERFLOC A-120, SUPERFLOC A-130, andSUPERFLOC A-150 HMW, all of which are anionic polyacrylamide flocculantsfrom Cytec Industries. Another example is MAGNAFLOC 1011, a highmolecular weight anionic polyacrylamide flocculant from Ciba SpecialtyChemicals. In a preferred embodiment, the powder comprises about 25% ofthe slurry, but can range from 20% to 40% and still be effective.

Component 3: water. The water is preferably added to the dispensingslurry en route to the targeted surface at a preferred ratio of about 10parts water to about one part slurry (volume or weight), or about 10parts of slurry to about 100 parts of water. Water can be added inratios as little as 5 parts water to one part slurry and ratios as highas 40 parts water to one part slurry.

Component 1 provides a very low coefficient of friction (less than0.01), but by itself is not as effective at denying mobility toperseverant personnel or vehicles without the addition of the granularpolymer powder. As both materials become hydrated, the emulsion becomesa sticky cohesive semi-fluid mass and the acrylic powder is held withinthat mass as a swollen particle that provides a propping effect thatgreatly limits mobility. Unlike wet ice, it is more difficult to adjustone's stride or velocity to prevent slipping and falling, regardless offootwear or treaded tires, especially on hard or compacted surfaces. Onuncompacted surfaces and soils, cleated shoes, steel studded tires ortank treads may be able to possibly penetrate the film to a moretrackable and passable and maneuverable condition, but not withoutdifficulty and not without still having the progress significantlyimpaired due to the slippery conditions imparted by the anti-tractionmaterial.

One of the novel aspects of this invention is believed to lie in thesurprising effectiveness of the combined materials (water, emulsion andswollen solids) that prevents mobility and access to controlled sitesregardless of speed, footwear or vehicle wheel structures when appliedto hard surfaces such as asphalt, concrete and compacted soils. It isequally effective on flat and sloping surfaces, as well as on grassyterrain, either mowed or heavily vegetated.

The anti-traction composition of the invention is preferably made byfirst forming a slurry of the emulsion and the polymer particle, andthen subsequently combining it with the water component at the time ofapplication. The emulsified polymer and the acrylic polymer particle arefirst combined to form a slurry by mixing the two components at thecorrect ratio. Mixing is accomplished by stirring the acrylic polymerparticles into the emulsion. For small batches, this can be done using apaint stirrer, but for larger quantities, an electric or other typemixer may be required.

The anti-traction material may also comprise other components added intoeither the slurry and/or the emulsion as desired and/or needed. Forexample, malodorants, other noxious chemicals, colorants (e.g., tocamouflage the material), etc. can also be added to either the slurryand/or emulsion. Preferably, such additional components are included inamounts that are effective without destroying the lubricious and/orstickiness properties of the anti-traction material. However, slightreductions in lubriciousness may be tolerated. It is also preferred thatthe additional components not destroy the environmental friendliness ofthe anti-traction material.

Once the slurry is prepared, water is added at a ratio of about 20 partsof water to about 1 part of slurry (by volume or by weight), when beingapplied to hard, smooth surfaces. On rough and/or uneven surfaces, thepreferred ratio is about 10 parts of water to about 1 part of slurry.

Water is combined with the slurry upon immediate application to atargeted surface. If water is added to the slurry in the delivery systemprior to dispensing, gellation and/or clogging of the parts of thedelivery system most likely will occur. Since the water and slurry mustbe kept separated until dispensed, a special mixing nozzle is requiredthat allows the two fluids to come together at the exit point of thesystem. Water can also be added to the slurry after the slurry has beenapplied to the targeted surface. This approach is especially useful whendestruction of the surface (i.e. asphalt runway, road, etc.) isdesirable. The slurry could be pre-mixed and stored in sealed containersuntil ready for use if so desired.

There are several means by which the anti-traction material may bedelivered for use on hard surfaces. The anti-traction material can bepumped, sprayed, poured or even air-dropped to the desired location. Inone embodiment, once the slurry is in place, water is added and theanti-traction property takes effect. The required thickness of theapplied anti-traction material depends on several factors including thetype of surface that it is being applied to (i.e. asphalt, wood,concrete, grass), the surface temperature, and the porosity of thesurface. For example, for the anti-traction material to be effective onasphalt, a minimum thickness of 0.050″ is required, whereas on tile, aminimum thickness of 0.028″ is required.

The present invention may be used to slow or hinder the forward movementof others in several ways. First, the anti-traction material may bepositioned in or around an area into which one desires to keep othersfrom entering. It is preferred that in such circumstances that theanti-traction material be positioned on hard surfaces such as concrete,asphalt, compacted soils, etc.

When the anti-traction materials are positioned on such surfaces, onefinds it extremely difficult, if not impossible, to enter into therestricted area over or through the anti-traction material because aperson or vehicle is unable to obtain any traction or friction with theanti-traction material. As such, the person is unable to propel in anydirection, forward, back, etc., since the force of friction between thebody and the anti-traction material is so minute. The coefficient offriction between a body and the anti-traction material of the inventionis less than 0.01. As a comparison, ice has a coefficient of friction ofabout 0.05.

In addition to disrupting the motion of a person, the anti-tractionmaterial obstructs motor and other, land-based vehicles from entering arestricted/defended area. Like the person on foot unable to propelhimself because the force of friction is so minute between his body andthe anti-traction material, a land-based vehicle is also unable to gaintraction and cannot move through or over the anti-traction material. Amaterial is deemed “untrafficable,” or not navigable if the material hasa coefficient of friction less than 0.05. The material has a coefficientof friction between the material and the vehicle of less than about0.01.

Treads, regardless of the footwear or tires, do not overcome theanti-traction material wherein the anti-traction material is on a hardsurface, e.g., concrete, asphalt, compacted soil, thus obstructing themovement of both persons and land-based vehicles.

It has been found that propelling oneself or another to “slide over” theanti-traction material may also result in the propelled person and/orobject being coated with the anti-traction material. Thus, even if thepropelled person or vehicle is able to advance through the anti-tractionmaterial application area, the person and/or vehicle still finds itdifficult to maneuver thereafter as the anti-traction material coatingstill on the person/vehicle continues to hinder movement and/or graspingor holding of objects. This is especially true since the anti-tractionmaterial is not easily removed from the person or vehicle when thematerial is wet.

It is also not advantageous to build a “bridge” over the anti-tractionmaterial by laying materials, e.g., boards, other persons, etc., overthe anti-traction material because the bridge materials will tend toslide out of position as the person/vehicle tries to cross over thebridge. If the bridge materials are not secured to an area not coatedwith the anti-traction material, the bridge materials will be forced tomove in a direction opposite the force exerted by a person/vehiclemoving across the bridge materials. This is because the person crossingthe bridge must push off the bridge materials to move forward. However,if the bridge materials are not secured to an area not coated with theanti-traction material, the movement of the person/vehicle crossing thebridge will push the bridge materials away.

If the anti-traction material is dispensed on uncompacted surfaces,i.e., loose soils, there is a higher probability that a person and/orland vehicle might be able to gain enough traction depending on thetread of the footwear or tires. However, the material still hinders theperson/vehicle's movement, albeit to a less significant degree than itwould otherwise, but is still useful in limiting the movement of theperson/vehicle.

The anti-traction material is not limited only to use on horizontal hardsurfaces to impede movements by foot or by land vehicle. Theanti-traction material may also be applied to sloped and/or verticalstructures and regions due, in part, to the high cohesiveness of thematerial.

The anti-traction material may be most effective when it is distributedin a random pattern over a surface, thereby creating slippery andnon-slippery surfaces. Such a random dispersement makes people even lesssure of their steps if they attempt to cross the coated surface. Thisalso reduces the effectiveness of people from running and sliding acrossthe anti-traction material because of the randomness of the applicationand the carryover of material from a treated area to an untreated areavia people's footwear.

The anti-traction material may further be placed on the surfaces ofdevices to keep others from utilizing them. For example, one could placea coating of the anti-traction material on windows, doorknobs, railings,stairways, entryways, etc. to restrict someone from entering or leavingan area.

It is particularly effective in preventing the scaling of walls andstairwells and makes doorknobs and railings impossible to grip. Ifsprayed on weapons, steering columns, tools and the like, their utilityis impaired. Exceptional effort is required to remove the anti-tractionmaterial through hot water or high-pressure washing with copious amountsof water.

The material can be removed if desired (e.g., after accomplishing thegoal of the use) by high-pressure water, hot or cold, and displaced fromthe targeted areas to peripheral sights. It dries to a sweepable film,but can be easily reconstituted to its original anti-traction state byreapplication of water thereto.

Among other things, the present invention thus provides:

(a) a slurry of an emulsified acrylic polymer in water//petroleumdistillate with a granular anionic acrylamide, which, when combined withwater, forms a viscous, highly lubricious, greatly displacementresistant film, which adheres to vertical as well as horizontalsurfaces;

(b) a water-activated slurry which provides a non-displaceable,film/coating that impedes traffic;

(c) a renewable, anti-traction coating which after drying can berestored to its original function by the application of water;

(d) a mobility denial mixture that can be pumped, sprayed, poured orairdropped to the desired target areas;

(e) a coating that may be applied to walls, doors, windows, railings,steps, grass, concrete, asphalt, or dirt surfaces to impede movement ofpersonnel or vehicles;

(f) a highly lubricious coating that can render tools, weapons, and anyhand-operated device difficult or impossible to operate; and

(g) a highly tenacious, lubricious coating that requires extraordinarymeans to remove: great volumes of water or water high pressure with orwithout heat.

While this invention has been described in conjunction with the specificembodiments outlined above, it is evident that many alternatives,modifications and variations will be apparent to those skilled in theart. Accordingly, the preferred embodiments of the invention as setforth above are intended to be illustrative, not limiting. Variouschanges may be made without departing from the spirit and scope of theinvention.

1. A method of producing a lubricious coating for reducing mobility overa target surface comprising: forming an emulsion or dispersion in waterof a polymer and dispersed in an oil phase selected from the groupconsisting of polyacrylamides, polyacrylates, polyacrylic acids, andcopolymers thereof; mixing the emulsion or dispersion with an acrylic oracrylamide polymer particles at a particle size of about 0.5 mm to 2.0mm to form a slurry; combining the slurry with water at 5-40 parts waterto one part slurry by volume or weight; and coating at least a portionof said target surface with said lubricious coating, wherein the wateris added to the slurry as the slurry is dispensed to said target surfaceand forming said viscous gel coating on said target surface.
 2. A methodof producing a lubricious coating for reducing mobility over a targetsurface comprising: forming an emulsion or dispersion in water of apolymer and dispersed in an oil phase selected from the group consistingof polyacrylamides, polyacrylates, polyacrylic acids, and copolymersthereof; mixing the emulsion or dispersion with an acrylic or acrylamidepolymer particles at a particle size of about 0.5 mm to 2.0 mm to form aslurry; combining the slurry with water at 5-40 parts water to one partslurry by volume or weight; and coating at least a portion of saidtarget surface with said lubricious coating, wherein the water is addedto the slurry after the slurry is dispensed to said target surface andforming said viscous gel coating on said target surface.
 3. The methodaccording to claim 1, wherein the emulsion or dispersion comprises about75% of the slurry, and the acrylic or acrylamide polymer comprises about25% of the slurry.
 4. The method according to claim 1, wherein a ratioof the water to the slurry is about 20:1 by volume or by weight.
 5. Themethod according to claim 1, wherein a ratio of the water to the slurryis about 10:1 by volume or by weight.
 6. The method according to claim2, wherein the emulsion or dispersion comprises about 75% of the slurry,and the acrylic or acrylamide polymer comprises about 25% of the slurry.7. The method according to claim 2, wherein a ratio of the water to theslurry is about 20:1 by volume or by weight.
 8. The method according toclaim 2, wherein a ratio of the water to the slurry is about 10:1 byvolume or by weight.
 9. The method according to claim 1, wherein theemulsion or dispersion comprises about 60-80% of the slurry and theacrylic or acrylamide polymer comprises about 20-40% of the slurry. 10.The method according to claim 1 wherein the lubricious coating is formedat a thickness of at least 0.28 inches.
 11. The method according toclaim 2, wherein the emulsion or dispersion comprises about 60-80% ofthe slurry and the acrylic or acrylamide polymer comprises about 20-40%of the slurry.
 12. The method according to claim 2 wherein thelubricious coating is formed at a thickness of at least about 0.28inches.